Search, imaging and identification and imaging of relatively small objects within relatively large volumes and at short ranges is an important challenge that has not been met yet for many years, despite tremendous efforts that have been carried out in many sensing disciplines. Meeting this challenge has practical applications in many regions of our life such as un-noticeable identifying of concealed metal objects on a person's body or electromagnetic medical imaging of human body.
Conventional thought is to use two major sensing candidate disciplines for the above challenge: electromagnetic and electro-optics (optical sensing). Each discipline has advantages and disadvantages. The optical sensing advantages include high angle and cross range resolutions and nearby capability, however limited in searching of large volume arenas and in range resolution and accuracy. The electromagnetic sensing provides large volume search advantage and range resolution and accuracy, however generally limited in angle and cross range resolutions and in nearby arena search. Some conventional implementations, while theoretically possible, are unacceptable for use in situations involving humans, as the power required for conventional implementation is considered hazardous to human health.